create a fake infix operator

 Sub::Infix creates fake infix operators using overloading. It doesn't
 use source filters, or Devel::Declare, or any of that magic. (Though
 Devel::Declare isn't magic enough to define infix operators anyway; I
 know; I've tried.) It's pure Perl, has no non-core dependencies, and
 runs on Perl 5.8.